/Engine/Source/Editor/UnrealEd/Public/Editor.h
Delegate type for triggering when new actors are dropped on to the viewport via drag and drop
typedef TMulticastDelegate_TwoParams< void, const [TArray](API\Runtime\Core\Containers\TArray)< [UObject](API\Runtime\CoreUObject\UObject\UObject) * > &, const [TArray](API\Runtime\Core\Containers\TArray)< [AActor](API\Runtime\Engine\GameFramework\AActor) * > & > FOnNewActorsDropped